Tin-halide perovskites for light-emitting diodes

Tin-halide perovskite light-emitting diodes (PeLEDs) have garnered significant attention due to their exceptional potential in achieving high-performance and eco-friendly light-emitting devices. Tin-halide PeLEDs have recently achieved notable breakthroughs in device efficiency, spectral tunability, and long-term operational stability. However, the facile oxidation of Sn²⁺ and rapid crystallization kinetics have substantially constrained their further development. The oxidation of Sn²⁺ and fast crystallization of the perovskite layer lead to a p-doping nature and high defect densities, which result in low photoluminescence quantum yield (PLQY) and unbalanced charge injection. Therefore, an in-depth understanding of the oxidation and crystallization processes is key to the further advancement of tin-halide PeLEDs. In this review, we discuss the basic properties of tin-halide perovskites. A comprehensive analysis of the fundamental mechanisms underlying the efficiency limitations and stability issues in these devices is provided. Subsequently, we present the latest advances in achieving efficient and stable operation, which provides a clear set of design rules for the development of high-efficiency and stable tin-halide PeLEDs. The remaining challenges and perspectives toward developing high-efficiency and stable optoelectronic devices are also discussed, with the aim of optimizing the PLQY, emission wavelength control, balanced charge injection, and commercialization.